#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int main()
{
	int arr[10] = { 0 };
	int sum = 0;
	float average;
	for (int i = 0; i < 10; i++)
	{
		scanf("%d", &arr[i]);
		sum += arr[i];
	}
	average = (float)sum / 10;
	printf("%.2f", average);
	return 0;
}